In an image pickup device, display device, or another image device, or in a photomask for manufacturing such devices, nonuniformity defect examination is conventionally available as an option for examining patterns formed on a surface. Nonuniformity defects are errors with a different regularity that has unintentionally occurred in a pattern with a regular arrangement, and these defects occur due to some cause in the manufacturing step or another process.
When nonuniformity defects are present in image pickup devices and display devices, sensitivity nonuniformities and display nonuniformities occur, and the device performance is liable to decrease. When nonuniformity defects occur in photomask patterns that are used in the manufacture of image pickup devices and display devices, the performance of the image device may decrease because the nonuniformity defects are transferred to the pattern of the image device.
Conventionally, nonuniformity defects in photomask patterns and patterns of image devices as described above often cannot be detected in shape examinations of individual patterns due to the fact that microdefects are ordinarily arranged in a regular fashion, but when the area is viewed overall, the defective portion is different than other areas. For this reason, nonuniformity defect examination is mainly carried out by visual examination in oblique light or other examination of the external appearance.
However, since this visual examination has a drawback in that there is variation in the examination result depending on the worker, a device for examination of nonuniformity defects such as that in JP-A 10-300447, for example, has been proposed. The device for examination of nonuniformity defects of JP-A 10-300447 emits light to a substrate on whose surface a pattern is formed, and detects nonuniformity by sensing scattered light from the edge portion of a pattern by using a CCD line sensor.
However, nonuniformity defects include a variety of nonuniformity defects in which the shape, regularity, and other factors are different depending on the cause of the defect or the like, for example. Nevertheless, there is a danger that each of a plurality of types of nonuniformity defects which require detection cannot be detected with high sensitivity in a conventional device for examination of nonuniformity defects that has the device for examination of nonuniformity defects of JP-A 10-300447.
The present invention was contrived with consideration given to the above-described situation, and an object thereof is to provide a pattern nonuniformity defect examination method and a pattern device for examination of nonuniformity defects that can detect with high precision a plurality of types of nonuniformity defects that occur in a pattern formed on the surface of an examination object.